1. Field of the Invention
This invention relates to an unlocking device for use in a seatbelt system for unlocking an emergency locking device, and particularly to an unlocking device for allowing the windoff of a webbing of the seatbelt system as necessary.
2. Description of the Prior Art
There has been proposed an automatically fastening type seatbelt system wherein an outer end of an occupant restraining webbing is solidly secured to a frame of a door for entering and leaving the vehicle, whereby the intermediate portion of the webbing is adapted to pass over the occupant and to approach or separate from the occupant in response to the action of the door during opening or closing the door, so that the seated occupant can be automatically restrained or unrestrained in the seat of the webbing. In the seatbelt system above-mentioned, it is possible to automatically fasten the webbing to the occupant merely by the action of the door closing after the occupant is seated on the seat. Moreover, in an emergency of the vehicle, an inner end portion of the webbing is wound up and a retractor installed at the substantially central portion of the vehicle is adapted to instantly hinder the windoff of the webbing by the operation of an emergency lock mechanism, so that the occupant is reliably restrained, thereby improving the safety of the occupant.
However, in the seatbelt system as described above, when the vehicle is stopped in a condition of being tilted more than a given angle after a collision of the vehicle, the emergency lock mechanism still locks a takeup shaft of the retractor, thereby the restrained webbing hinders the opening of the door. That is, the occupant cannot escape from the compartment of the vehicle by the locking action of the webbing. For this reason, there has been already proposed an unlocking device for unlocking the emergency lock mechanism of the retractor from its operation as necessary.
An application concerning an unlocking device was filed on November 13, 1978 before Japanese Patent Office, whose number of laid open publication is Utility Model application No. 52-72962 . An unlocking knob of the unlocking device is designed to be operated so as to allow the webbing to be wound off from the retractor as necessary, so that the door can be opened.
It is necessary for the unlocking knob to be installed at a position where the unlocking knob is very easily operable by the occupant in an emergency of the vehicle, and further, there is a need that the unlocking knob does not hinder the operation of the emergency lock mechanism. As viewed from this point, the unlocking knobs which have been developed heretofore have not been satisfactory.